If two non-zero vectors can not be represented by the same directed line segment, then the two vectors are not equal and the proposition is true Among the three elements of a directed line segment, there are starting points. The starting points are different, and the directed line segments are different. The vector has nothing to do with the starting point, but only the size direction. So it should be a false proposition, but it will be dead. In the fourth assignment, it is said that this is a true proposition,

If two non-zero vectors can not be represented by the same directed line segment, then the two vectors are not equal and the proposition is true Among the three elements of a directed line segment, there are starting points. The starting points are different, and the directed line segments are different. The vector has nothing to do with the starting point, but only the size direction. So it should be a false proposition, but it will be dead. In the fourth assignment, it is said that this is a true proposition,

If two non-zero vectors cannot be represented by the same directed line segment, then the two vectors are not equal. This is a true proposition. Of course, an equal vector can be represented by the same directed line segment

In the plane, there are two vectors M = (COS α, sin α), n = cos β, sin β), and (0 ＜ α ≤ β ≤ π) (1) find the value range of M * n
(2) If the angle between two vectors is an obtuse angle, find the value range of α

m.n
=(cosα,sinα).(cosβ,sinβ)
= cosαcosβ+sinαsinβ
=cos(α-β)
-1